Concrete is used for a multitude of different applications including the formation of substantially horizontal, hard surfaces commonly referred to as flatwork. The concrete is initially formed into a pourable and workable substance comprising cement, rock aggregate, water, and other additives. The concrete is then poured into forms or other containing structures where it hardens, or "cures". As the concrete begins to harden, it is generally worked with trowels, troweling machines or various other instruments in order to obtain a relative uniform, non-wavy, durable surface. As a result of such activity, the surface of the concrete may obtain a relatively smooth texture, which can be dangerous for some applications--such as sidewalks, driveways, highways, and the like--particularly when the surface is damp, frosty or icy.
To minimize such dangers, the concrete is given a roughened surface as it is hardening, sometimes referred to as a "broom" finish. Such roughening is sometimes accomplished by pushing or dragging the bristles of a broom across the surface of the hardening concrete in a direction generally perpendicular to the anticipated flow of traffic on that surface. As a result, the surface is scored with randomly spaced bristle marks, which marks harden in the surface of the concrete thereby providing a surface which minimizes tendencies for slipping.
The degree of scoring for a particular surface generally depends on the anticipated use of that surface. Sidewalks and patios, which are primarily exposed only to foot traffic, for example, need only light or fine scoring to provide a slip-resistant surface. On the other hand, highways, streets, parking lots and bridges, which are primarily subjected to vehicular traffic as opposed to foot traffic, generally require much coarser scoring in order to provide a slip-resistant surface for the vehicles traveling therealong.
It is well known to use a garage-type push broom or brush to roughen or score the surface of concrete. Such brushes typically have a width of two feet, or less. Some prior art brushes specially manufactured for finishing concrete have widths of 24, 36 or 48 inches. The bristles thereof, which are generally constructed of polypropylene, horsehair, or nylon, are generally staple set or otherwise formed into channel style strips in a wooden head such that the bristles extend generally perpendicularly downwardly from the wooden head. Another problem with the wooden heads of prior art brushes is the relatively rapid deterioration of the wooden heads due to exposure thereof with the corrosive constituents of the concrete material.
To maneuver the brush over the surface of the wet concrete, the brush head is generally attached to the end of a long handle having a sufficient number of sections attached end-to-end such that a user can reach either entirely across the flatwork or at least half-way across, depending on the width of the flatwork. The user then places the bristles of the brush against the flatwork at the side of the flatwork nearest the user and uses the handle to push the brush in a straight line to the side of the flatwork opposite from the user (or slightly beyond midway as the case may be).
Then, using the handle as a lever, the user lifts the brush clear of the flatwork and maneuvers the brush to a new position on the flatwork immediately adjacent to that from which the brush was lifted. In fact, the brush is spaced such that the return path to be swept by the brush slightly overlaps the previous path in order to avoid leaving an unroughened strip of concrete between the adjacent sweeps. The handle is then used to pull the brush back to the side of the flatwork nearest the user. The described process is repeated until either the entire surface, or half of the surface nearest the user, is "broomed". If only half of the surface is reachable by the long handle, the user then proceeds to the opposite side of the flatwork to broom the remaining half of the flatwork.
Depending on the length of the handle, a considerable torque or moment must sometimes be applied by the user to lift the brush from the concrete, particularly since the brush becomes gradually heavier due to the concrete that accumulates in and on the brush during use. Additional responsibility is placed on the user to avoid allowing the brush to drop back against or bump the surface of the concrete as the bristles are directed substantially perpendicularly to the surface and can easily gouge concrete material from the surface.
Another complication arising from the use of a prior art concrete finishing brush is the long handle, while limits the user's ability to use it in congested or crowded quarters, such as inside a building or near surrounding structures, due to interference with the necessary path of the long handle during the pulling and pushing procedure inherent in concrete finishing with a brush having a long handle.
The channel strip-type brushes used in prior art devices have essentially no gaps between the bristles, just one straight row of continuous bristle fill. As a result, such channel strip-type brushes tend to pull or squeegee the "cream" from the surface of the flatwork concrete. In an attempt to avoid this undesirable effect, some prior art concrete finishing brushes have been constructed with staple set-type bristles which pull or squeegee less "cream" than channel strip-type brushes due to a multiple-row configuration of the bristles, wherein each row has a plurality of equally spaced gaps between clusters of bristles, with the gaps of a consecutive row(s) staggered to fill the gaps of the adjacent row(s).
Factors affecting the roughness of the broomed finish include, among other things, the stiffness of the bristles, the angular orientation of the bristles at their point of contact with the flatwork, the softness or "green"-ness of the concrete at the time the roughening finish is applied, etc. As the bristles of most of the prior art brushes are generally approximately perpendicular to the surface of the flatwork, the brush must not be applied too quickly after the "pour", such as when the concrete has just been "floated" and is very soft and creamy. Otherwise, the tips of the bristles will gouge too deeply into the concrete surface or will scrape off the "creamy" surface and expose the aggregate, or both. As a result, brooming of the flatwork concrete with prior art concrete finishing brushes is generally delayed until the concrete begins to "set" whereby it can more readily endure the abusiveness to the flatwork arising from contact with brushes having bristles oriented substantially perpendicularly to the flatwork.
Many times during such delay of using a prior art finishing device, a user may get distracted and not realize that the concrete has hardened more than intended; in other words, the user has waited too long and the concrete has "set" or hardened to the point that the weight of the brush is more easily supported by the green flatwork. Even though some roughening may still be possible, the extent thereof may be substantially less than that desired in order to obtain a slip-resistant surface. Under those circumstance, the user sometimes attempts to enhance the effect of the brooming procedure by tying weights to the brush. Such remedial measure may not provide a practical solution, however, particularly if the user must lift that extra weight at the end of a long handle for the return sweep. In addition, the added weight may cause the surface to become more uneven as some portions of the surface may have cured slightly earlier than other portions of that surface.
What is needed is a concrete finishing tool that substantially uses the sides of the bristles instead of the ends of the bristles for "brooming" flatwork concrete, that does not require the use of a long handle, that can be used to "broom" the entire width of flatwork even though the flatwork may have virtually unlimited width, that can be used to easily sweep strips having widths substantially greater than four feet, that can be used to uniformly and reliably "broom" a flatwork surface shortly after the concrete is poured thereby avoiding the risk of delaying too long before brooming, that avoids the costs of personnel who might not otherwise be overly productive while waiting for the flatwork to partially set as required by prior art concrete finishing devices, that can be used in congested spaces, and that can be quickly disassembled for use with either a push-pin handle or a screw-on handle in a conventional manner while preserving the ability to broom concrete substantially with the sides of the bristles as opposed to the ends of the bristles.